1. Field of the Disclosure
Embodiments of the present disclosure relate generally to image processing technologies and more specifically to truncation correction imaging enhancement methods and systems.
2. Description of the Related Art
Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Computed tomography (CT) has been a widely used imaging technique. However, when a CT medical imaging device takes an insufficient number of samples aliasing artifacts such as streaks may appear in the reconstructed images. Cone-beam computed tomography (CBCT), which involves the use of wide area detectors, is more susceptible to undersampling problems because data frame rates are slower.
One challenge for medical cone-beam computed tomography is to manage respiratory motion. Due to the relatively slow gantry rotation times, it is very difficult to acquire a full CBCT data set in a single breath hold, much less in a single respiratory phase (e.g., inspiration or expiration). However, because motion is periodic, a 4-D image (3 spatial dimensions and 1 time dimension) can be obtained by grouping the acquired CBCT projections by respiratory phase and reconstructing a distinct 3-D image for each phase. In many cases, due to the sparse or “wagon-wheel” projection sampling distributions associated with each respiratory phase, aliasing artifacts, including streaks emanating from bones, are often introduced. While it is possible to reduce these artifacts by slowing down the gantry rotation rate thus reducing the distance between adjacent wagon-wheel spokes, there are substantial costs associated with lengthening the imaging times and delivering higher doses of radioactive X-rays.
Another challenge for CT image reconstruction is that during the scanning of a patient, other objects, such as a patient table, may also lead to streaks in reconstructed images. For instance, a portion of the patient table may be truncated, and this truncated portion is not included as a part of all the acquired projections. The truncated portion, causing incomplete and inconsistent data, may thus contribute to the occurrence of streaks or other artifacts in the reconstructed images.